HDX-MS study on garadacimab binding to activated FXII reveals potential binding interfaces through differential solvent exposure

MAbs. 2023 Jan-Dec;15(1):2163459. doi: 10.1080/19420862.2022.2163459.

Abstract

Hageman factor (FXII) is an essential component in the intrinsic coagulation cascade and a therapeutic target for the prophylactic treatment of hereditary angioedema (HAE). CSL312 (garadacimab) is a novel high-affinity human antibody capable of blocking activated FXII activity that is currently undergoing Phase 3 clinical trials in HAE. Structural studies using hydrogen/deuterium exchange coupled to mass spectrometry revealed evidence of interaction between the antibody and regions surrounding the S1 specificity pocket of FXII, including the 99-loop, 140-loop, 180-loop, and neighboring regions. We propose complementarity-determining regions (CDRs) in heavy-chain CDR2 and CDR3 as potential paratopes on garadacimab, and the 99-loop, 140-loop, 180-loop, and 220-loop as binding sites on the beta chain of activated FXII (β-FXIIa).

Keywords: HDX-MS; Hageman factor; SPR; binding stoichiometry; epitope mapping; negative stain electron microscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Binding Sites, Antibody
  • Factor XII* / chemistry
  • Factor XII* / metabolism
  • Humans
  • Hydrogen / chemistry
  • Hydrogen Deuterium Exchange-Mass Spectrometry*

Substances

  • Factor XII
  • Hydrogen

Grants and funding

This study was supported by CSL Ltd. Parkville, Australia;CSL Limited.